Cleanup LocalDiscoveryUIHandler.

chrome/browser/extensions/api/cloud_print_private/cloud_print_private_api.cc

Index: chrome/browser/extensions/api/cloud_print_private/cloud_print_private_api.cc
diff --git a/chrome/browser/extensions/api/cloud_print_private/cloud_print_private_api.cc b/chrome/browser/extensions/api/cloud_print_private/cloud_print_private_api.cc
index 2f590068b522982da0c1e9ebfe0a242cc3bfe831..a367bb1b0ada3460379312651e14e714a3acd804 100644
--- a/chrome/browser/extensions/api/cloud_print_private/cloud_print_private_api.cc
+++ b/chrome/browser/extensions/api/cloud_print_private/cloud_print_private_api.cc
@@ -48,16 +48,14 @@ bool CloudPrintPrivateSetupConnectorFunction::RunAsync() {
         params->credentials,
         params->user_settings);
   } else {
+    std::unique_ptr<base::DictionaryValue> user_settings(
+        params->user_settings.ToValue());
     CloudPrintProxyService* service =
         CloudPrintProxyServiceFactory::GetForProfile(GetProfile());
-    if (!service)
-      return false;

[Vitaly Buka (NO REVIEWS), 2016/04/16 01:33:52]

I guess this could be NULL for for incognito.

[Lei Zhang, 2016/04/16 01:53:19]

Ok, I will look into this. How is this API used anyway?

At least I passed all the existing tests. Should I add another API test and try
to use it in incognito?

At least my thought right now is:

- GetProfile() relies on UIThreadExtensionFunction's context.
- UIThreadExtensionFunction's context starts out NULL, but 
ExtensionFunctionDispatcher calls
UIThreadExtensionFunction::set_browser_context() before running any functions.
- ExtensionFunctionDispatcher's context comes from ExtensionWebContentsObserver.
- ExtensionFunctionDispatcher's context comes from a WebContents.
- WebContents should have a valid context?

[Vitaly Buka (NO REVIEWS), 2016/04/16 02:17:56]

Test would be nice.

This API used only by
https://www.google.com/cloudprint/enable_chrome_connector/enable.html.
chrome://devices only redirects to that page.

Try to navigate to
https://www.google.com/cloudprint/enable_chrome_connector/enable.html?proxy=N...

In normal tab you should see printers list. and "add" button.
Incognito should not crash. Now it displays empty list of printers and no "add"
button.
I suspect it will crash without if (!service).

If you know how disable API for incognito, then you probably can remove if
(!service).

-    std::unique_ptr<base::DictionaryValue> user_setings(
-        params->user_settings.ToValue());
     service->EnableForUserWithRobot(params->credentials,
                                     params->robot_email,
                                     params->user_email,
-                                    *user_setings);
+                                    *user_settings);
   }
   SendResponse(true);
   return true;
@@ -99,11 +97,7 @@ bool CloudPrintPrivateGetPrintersFunction::RunAsync() {
   if (CloudPrintTestsDelegate::instance()) {
     SendResults(CloudPrintTestsDelegate::instance()->GetPrinters());
   } else {
-    CloudPrintProxyService* service =
-        CloudPrintProxyServiceFactory::GetForProfile(GetProfile());
-    if (!service)
-      return false;
-    service->GetPrinters(
+    CloudPrintProxyServiceFactory::GetForProfile(GetProfile())->GetPrinters(
         base::Bind(&CloudPrintPrivateGetPrintersFunction::SendResults, this));
   }
   return true;